Development of a Blumlein based on helical line storage elements

Abstract

A Blumlein based on helical line storage elements was conceived and developed for generation of a rectangular pulse of 150 kV, 5 μs duration and which can drive a load of about 1 kΩ impedance. The helical line consisting of an aluminum tube of 750 mm length and 100 mm diam, wound with mylar film insulation to withstand 200 kV and then wound with copper wire was built and tested in our laboratory. It has a capacitance of 1.2 nF and has a characteristic impedance of 2 kΩ. The pulse generator built here, uses ten such coils in Blumlein configuration with five elements in parallel in each section giving total capacitance of about 10 nF. It has the advantages of compactness, simplicity, low cost, reliability, and high performance towards good flat top, low rise time, and small jitter. It can be designed to match load impedances in the range of a few ohms to several kilo ohms. This pulse power system was built and successfully tested for accelerating electrons in the gun chamber of an electron beam controlled CO2 laser operating in the single shot mode. This article describes the design, fabrication, and performance of the pulse power system.